The present application is directed, in general, to systems and methods for locating and/or communicating with mobile personnel and, in particular, to a system and method for integrating locating/communicating devices into the existing wireless communications backbone.
To provide more efficient use of police, rescue and security forces, many telephone systems provide an indication of the address of the telephone subscriber placing a telephone call to obtain the assistance of such forces. The use of the address of the telephone subscriber provides many advantages including the efficient, and often direct, routing of emergency telephone calls to the proper political subdivision serving the geographic location of the calling person and the reduction of the number of false alarms and crank calls. Of significant additional benefit to rescue and similar emergency personnel is the fact that the use of such locating systems in the telephone network provide the address of a caller who, because of physical impairment or the proximity of unfriendly personnel, may not be able to speak to the emergency services dispatcher. There are many recorded instances in which a person who was unable to speak, for example because the occurrence of a debilitating stroke, has been saved by the fact that the emergency personnel were provided by the telephone network with an indication of the location of the person needing assistance.
Generally, in prior art systems, the ability to provide location information to emergency personnel was limited to those calls made from land-based telephones, as contrasted with wireless telephones. Generally, integrated into the fixed telephone network is a one-to-one correspondence between the location of a telephone and its telephone number. The emergency service systems took advantage of that correspondence to identify the location of a telephone to emergency personnel from the preexisting ability of the telephone network to identify the telephone number (or source) of a telephone call. With the use of wireless systems, however, the one-to-one correspondence between a telephone instrument's location and its telephone number is no longer valid as the wireless telephone may be wandering anywhere within the radiating range of the wireless system and be able to place telephone calls, including emergency calls.
To provide emergency personnel responding to emergency calls received from wireless telephones, systems have been proposed which would locate the user of the wireless telephone through one method or another and provide such location information. Often such location methods use the fact that the wireless telephone is a radiating instrument and use various receiving devices to triangulate on the radiation emanating from the wireless telephone. Usually, in such locating systems, the locating system must interpret the signals used in the wireless system to identify the telephone making the emergency call. The locating systems then generally geolocate using a triangulation scheme based upon the receipt of the signal from the mobile instrument at several of the landbased receivers within a particular wireless system.
Present systems which geolocate on the radiated communication signal from a mobile communication device have several limitations. First, because the locating system must identify the mobile device from the communicated signal and each type of wireless system has a particular and unique format and protocol, such locating systems generally work with only one of the many different wireless systems presently installed. For example, a locating system which geolocated based on the communicated signal from a present day cellular telephone device would not be able to receive the signals from former mobile telephone systems still in use, such as the AMPS system, existing pager systems, SMR systems. Similarly, such locating systems would not be able to locate users using other systems such as the Marine mobile systems, the citizens band radio system, and other non-cellular systems. Further aggravating the problem for locating systems is the fact that presently there are many new wireless systems coming on-line (digital cellular systems, Personal Communications Systems, etc.) which the locating system will not be able to accommodate without the addition of substantial additional equipment to receive and decode the uniquely formatted and encoded signals from such new systems.
Further exacerbating the problems of locating persons within the many existing and soon-to-exist types of wireless systems is the fact that many of the systems are owned by or controlled by different entities, requiring considerable coordination in a commercially competitive arena which is often quite difficult to obtain.
Already there is a substantial installed base of mobile communications equipment, including mobile telephones and cellular telephones. To provide a emergency location system associated with the installed base could require the modification of most of the existing equipment, at a cost which both consumers and service providers would rather avoid. Consequently, any system to be developed to provide such locating capability should be readily integrable with the installed base along with being readily adapted with mobile communicating devices now and soon to become available.
Accordingly, it is an object of the present invention to provide a novel system and method for geolocating mobile communications devices without the need for extensive retrofitting of the installed base of such devices.
It is another object of the present invention to provide a novel system and method for geolocating mobile communications devices without impacting on the ability of the communications system to handle normal message traffic.
It is yet another object of the present invention to provide a novel system and method for geolocating mobile communications devices which can be automatically activated.
It is still another object of the present invention to provide a novel system and method for geolocating mobile communications devices which may be integrated into the plurality of different mobile communications systems presently and soon to be in existence.
It is a further object of the present invention to provide a novel system and method of geolocating mobile communications devices which have sufficient geolocating accuracy to identify the location of the user.
It is yet a further object of the present invention to provide a novel device for use in a geolocating mobile communications system wherein the device is relatively simple to manufacture and readily installed into a mobile communications environment.
It is still a further object of the present invention to provide a novel system and method for geolocating mobile communications units which obviates these and other difficulties experienced in present systems.